The relationship of newborn adiposity to fetal growth outcome based on birth weight or the modified neonatal growth assessment score

Figures & data

Figure 1.  Equations used for neonatal growth assessment score. WT, weight; HC, head circumference; AC, abdominal circumference; ThC, mid-thigh circumference; CHL, crown–heel length [19,20,39].

Table I.  Percentage body fat and fat mass percentiles by post-menstrual age (n = 324).

WK	n	Weight ± 1 SD	5th percentile	10th percentile	25th percentile	50th percentile	75th percentile	90th percentile	95th percentile
35	25	2695 ± 419	1.5 (19)	2.9 (56)	5.2 (118)	7.7 (186)	10.3 (254)	12.6 (316)	14.0 (353)
36	34	2793 ± 340	2.1 (37)	3.5 (79)	5.8 (150)	8.4 (228)	11.0 (306)	13.3 (376)	14.7 (418)
37	36	3037 ± 410	2.8 (55)	4.2 (102)	6.5 (182)	9.1 (269)	11.6 (357)	13.9 (436)	15.3 (483)
38	66	3233 ± 500	3.5 (73)	4.9 (126)	7.2 (213)	9.8 (311)	12.3 (408)	14.6 (496)	16.0 (548)
39	91	3497 ± 504	4.2 (91)	5.6 (149)	7.9 (245)	10.4 (352)	13.0 (459)	15.3 (556)	16.7 (613)
40	43	3536 ± 503	4.8 (109)	6.2 (172)	8.5 (277)	11.1 (394)	13.7 (511)	16.0 (616)	17.4 (679)
41	29	3882 ± 447	5.5 (127)	6.9 (195)	9.2 (309)	11.8 (436)	14.3 (562)	16.6 (676)	18.0 (744)

Fat mass (g) is expressed in parentheses.

Weight, neonate weight (g) at time of body composition study; WK, post-menstrual age in weeks.

Figure 2.  Body fat versus post-menstrual age expressed as percentage (a) or absolute amount (b) of body fat. Regression equation for percentage body fat = −15.9 + 0.675 × weeks, r² = 0.075, p < 0.001; for fat mass = −1270 + 41.6 × weeks, r² = 0.152, p < 0.001. Regression lines = predicted mean value with 5th and 95th percentiles. While the standard deviation in percentage body fat did not significantly change as post-menstrual age increased, the standard deviation in fat mass increased with increasing post-menstrual age. SGA, small for gestational age; AGA, appropriate for gestational age; LGA, large for gestational age.

Figure 3.  Body fat versus neonatal weight at the time of air displacement plethysmography expressed as percentage (a) or absolute amount (b) of body fat. Regression equation for percentage body fat = −4.01 + 0.00447 × weight, r² = 0.370, p < 0.001; for fat mass = −461 + 0.251 × weight, r² = 0.623, p < 0.0001. Regression lines = predicted mean value with 5th and 95th percentiles. While the standard deviation in percentage body fat did not significantly change as newborn weight increased, the standard deviation in fat mass increased with larger newborn weight. SGA, small for gestational age; AGA, appropriate for gestational age; LGA, large for gestational age.

Figure 4.  Effect of gender on percentage body fat (%BF) and fat mass. Females had slightly greater mean %BF (10.8 ± 4.2%) when compared to male neonates (9.5 ± 3.6%) (t-test = 2.98, p = 0.003) (a). These differences disappeared when mean fat mass was compared between females (351 ± 183 g) and males (323 ± 161 g) (t-test = 1.47, p = 0.14) (b). On average, males had 2.3 ± 0.34% less %BF (t = 6.78, p < 0.0001) and 78 ± 11 g less FM than females (t = 6.94, p < 0.0001). Both graphs show mean ± 1 SD for each group.

Figure 5.  Nutritional classification of percentage body fat and fat mass using population-based weight standards. No significant differences were found between groups by either percentage body fat (a), (ANOVA, F ratio = 0.37, p = 0.69), or fat mass (b), (ANOVA, F ratio = 0.14, p = 0.87); similarly, all pairwise comparisons were not significant. Mean values ± 1 SD. SGA, small for gestational age; AGA, appropriate for gestational age; LGA, large for gestational age.

Figure 6.  Nutritional classification of percentage body fat and fat mass using a neonatal growth assessment score (m₃NGAS₅₁). The same subset of 92 neonates from Figure 5 is stratified into different nutritional groups: intrauterine growth retardation (IUGR, n = 7), normal (n = 81) or macrosomia (n = 4). Significant differences were observed for both percentage body fat (a), F ratio = 7.85, p < 0.005, and fat mass (b) (ANOVA, F ratio = 11.9), p < 0.001. Mean value ± 1 SD are shown; all pairwise comparisons were significant at p < 0.05. SGA, small for gestational age; AGA, appropriate for gestational age; LGA, large for gestational age.

Table II.  Neonatal nutritional classification: comparison between population standard versus modified neonatal growth assessment score (m3NGAS51)

n = 92	SGA	AGA	LGA
IUGR	1	6	0
Normal	9	65	7
Macrosomia	1	3	0

The correlation between both classification systems was not better than random chance on the basis of Kappa agreement (−0.011, p > 0.05) or Chi-Square (1.64, p = 0.80). Population standard [18].

SGA, small for gestational age; AGA, appropriate for gestational age; LGA, large for gestational age. Modified neonatal growth assessment score IUGR, intrauterine growth retardation [20].

Table III.  Newborn infant body composition-total body fat stores

Author	Lee (2012)	Koo (2004)	Schmeizie (2007)	Verkauskiene (2007)	Fields (2009)	Erickkson (2010)	Carberry (2010)	Roggero (2010)
Method	ADP	DXA	DXA	DXA	ADP	ADP	ADP	ADP
Subjects	324	120	124	159	117	108	45	59
Study age^a	22 h	3.0 days	4.1 days	72 h	20 days	8 days	0–4 days	3 days
MA (range)	38.6 ± 1.6 (35–41)	36.9 ± 2.5 (30–42)	39.7 ± 1.4 (37–42)	39.1 ± 1.6 (33–42)	39.3 ± 1.1 (≥37)	40 ± 1.1 (≥37)	40 ± 1.1 (37–42)	39.2 ± 1.3 (37–42)
Percentage body fat
Females	10.8 ± 4.2	14.3 ± 4.0	14.6 ± 5.4	19.2 ± 6.8	15.1 ± 5.9	13.4 ± 3.7	10.1 ± 4.4	8.7 ± 3.1
Males	9.5 ± 3.6	(Both genders)	(Both genders)	(Both genders)	12.7 ± 4.5	12.5 ± 4.0	9.4 ± 3.4	8.9 ± 2.3
Fat mass (g)
Females	351 ± 183	477 ± 210	510 ± 290	653 ± 304	588 ± 288	484 ± 173	331 ± 162	260 ± 120
Males	323 ± 161	(Both genders)	(Both genders)	(Both genders)	516 ± 227	484 ± 203	341 ± 149	290 ± 90

ADP, air displacement plethysmography; DXA, duel-energy X-ray absorptiometry; MA, menstrual age at time of birth reported with range.

^aStudy age (hours or weeks), age of infant body composition study after delivery

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